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Magneto-Infrared Spectroscopic Study of Ultrathin Bi2_{2}Te3_{3} Single Crystals

Abstract

Ultrathin Bi2_{2}Te3_{3} single crystals laid on Scotch tape are investigated by Fourier transform infrared spectroscopy at 44K and in a magnetic field up to 3535T. The magneto-transmittance spectra of the Bi2_{2}% Te3_{3}/tape composite are analyzed as a two-layer system and the optical conductivity of Bi2_{2}Te3_{3} at different magnetic fields are extracted. We find that magnetic field modifies the optical conductivity in the following ways: (1) Field-induced transfer of the optical weight from the lower frequency regime (<250<250cm1^{-1}) to the higher frequency regime (% >250cm1^{-1}) due to the redistribution of charge carriers across the Fermi surface. (2) Evolving of a Fano-resonance-like spectral feature from an anti-resonance to a resonance with increasing magnetic field. Such behavior can be attributed to the electron-phonon interactions between the % E_{u}^{1} optical phonon mode and the continuum of electronic transitions. (3) Cyclotron resonance resulting from the inter-valence band Landau level transitions, which can be described by the electrodynamics of massive Dirac holes

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